Self-tanning cosmetic composition

ABSTRACT

A self-tanning cosmetic composition containing dihydroxy acetone and a polyoxyethylene-polyoxypropylene block polymer type surfactant. The oil content is less than 10%. A self-tanning cosmetic gel containing dihydroxy acetone, water, alcohol, a water-soluble cellulose type thickening agent and/or xanthane gum and a chelating agent is also disclosed. This cosmetic composition produces a good feeling when applied to the skin and uneven coloration is adequately prevented.

TECHNICAL FIELD

The present invention relates to a self-tanning cosmetic compositionand, more particularly, to an improvement of a self-tanning cosmeticcomposition containing dihydroxy acetone.

BACKGROUND ART

A self-tanning cosmetic composition containing dihydroxy acetone(hereinunder referred to as "DHA" is intended to color the skin as if itwere tanned without being exposed to the sun (ultraviolet), and variousproducts are commercially available.

Those products are required to be uniformly applied to the skin in orderto prevent uneven coloring. They are generally produced in the form ofan emulsified product such as cream with the stability of the productcontaining DHA taken into consideration.

On the other hand, since a self-tanning cosmetic composition which doesnot contain oil can color the skin in a shorter time, a prescription ofa lotion which does not contain oil and is mixed with DHA is proposedwith importance set on a coloring ability to the skin.

However, since such a lotion does not spread well on the skin, uniformapplication is difficult, which results in uneven coloring of the skin.In other words, the finish in self-tanning is apt to be greatly damaged.

In addition, an aqueous self-tanning lotion has such a low viscositythat it often drips and causes unevenness in the color when it isapplied to the skin. That is, since there is a great problem in thefinish in self-tanning, the commercialization of the aqueous lotion isdifficult.

In order to eliminate the problem in a self-tanning lotion such asdripping and uneven coloration, attempts have long been made to add athickening agent to a self-tanning lotion so as to increase theviscosity.

For example, a method of adding a thickening agent which is representedby sodium polyacrylate (Carbopole 940, Carbopole 941, etc. produced byB.F.GOODRICH) to a prescription containing DHA has been investigated.However, this produces a great problem in the guarantee of the quality,because, for example, the stability of the viscosity with time isgreatly lowered due to the decrease in the pH caused by the addition ofDHA, and the external color of the product changes to brown with time.

In contrast, it is possible to prevent the color of a self-tanninglotion from changing to brown by using a nonionic thickening agent. Inthis case, however, it is also impossible to suppress the lowering ofthe viscosity with time. In addition, since the thickening effect of anonionic thickening agent is much lower than that of a polyacrylatethickening agent, it is necessary to add a large amount of nonionicthickening agent to obtain the same viscosity. In this case, the productbecomes tacky, which is peculiar to a polymer and produces an unpleasantfeeling when applied to the skin.

DISCLOSURE OF INVENTION

Accordingly, it is a first object of the present invention to eliminatethe above-described problems in the related art and to provide aself-tanning cosmetic which spreads well on the skin.

It is a second object of the present invention to provide a self-tanningcosmetic which can prevent dripping and uneven coloration, whichproduces a satisfactory feeling when applied to the skin, and which hasan excellent quality stability with time.

As a result of studies undertaken by the present inventors so as toachieve the first object, it has been found that a self-tanning cosmeticcomposition produced by adding DHA and a specific surfactant to a basehaving a low oil content can color the skin beautifully without a fearof uneven coloring. On the basis of this finding, the present inventionhas been completed.

A self-tanning cosmetic composition provided in a first aspect of thepresent invention is characterized in that the oil content is less than10%, and in that it contains DHA and a polyoxyethylene-polyoxypropyleneblock copolymer type surfactant.

To achieve the second object, it is necessary to add alcohol and achelate as well as a specific water-soluble thickening agent.

A self-tanning cosmetic gel provided in a second aspect of the presentinvention comprises DHA, water, alcohol, a water-soluble cellulosethickening agent and/or xanthane gum and a chelate.

BEST MODE FOR CARRYING OUT THE INVENTION

The structure of the present invention will be described in detail.

DHA used in the present invention is generally used in a self-tanningcosmetic composition and the amount of DHA used is generally about 1 to10 wt % of the total amount of self-tanning cosmetic composition withdue consideration of the coloring effect thereof to the skin.

The base applicable to the present invention is an aqueous basecontaining substantially no oil or an emulsion base having a low oilcontent. In the case of an emulsion base, the oil content is less than10%, preferably less than 5%.

If an emulsion base contains not less than 10% of oil, a self-tanningcosmetic composition which spreads well on the skin is obtained in therelated art, but it takes sometimes longer to color the skin with thecosmetic.

On the other hand, a self-tanning cosmetic produced from the basecontaining substantially no oil can color the skin with high clarity anda beautiful appearance.

As examples of the polyoxyethylene-polyoxypropylene block copolymersurfactant used in the present invention will be cited commerciallyavailable Pluronic and Tetronic (trade names: produced by Asahi DenkaKogyo K.K., BASF).

There are different grades of these surfactants in accordance with thenumber of moles of polyoxyethylene, and polyoxypropylene added but thegrade of the surfactant used in the present invention is not speciallyrestricted so long as the surfactant is soluble to the base.

The amount of polyoxyethylene-polyoxypropylene block copolymersurfactant added is 0.1 to 3 wt %, preferably 0.5 to 2 wt % of the totalamount of self-tanning cosmetic composition. If the amount ofpolyoxyethylene-polyoxypropylene block copolymer surfactant added isless than 1 wt %, it is impossible to improve the spreadability of thecosmetic to the skin. In order to improve the spreadability of thecosmetic to the skin, addition of 3 wt % ofpolyoxyethylene-polyoxypropylene block copolymer suffices and furtheraddition is not necessary.

As examples of the water-soluble cellulose thickening agent used in theself-tanning cosmetic gel of the present invention, methyl cellulose,hydroxypropyl cellulose hydroxypropylmethyl cellulose,hydroxypropylemethyl cellulose, and hydroxyethyl cellulose will becited, but it is not restricted thereto so long as the thickening agentis a nonionic cellulose thickening agent. The nonionic cellulosethickening agent is appropriately selected in accordance with theobject. The amount of water-soluble cellulose thickening agent added toa self-tanning cosmetic gel of the present invention is 0.1 to 2 wt %,preferably 0.5 to 1 wt % of the total amount of cosmetic composition. Ifit is less than 0.1 wt %, the thickening effect is low, so that it isimpossible to effectively prevent dripping and uneven coloration. On theother hand, if the amount exceeds 2 wt %, the cosmetic becomes tacky,which is peculiar to a polymer, and produces an unpleasant feeling whenapplied to the skin. If a xanthane gum is used together within theabove-described range, it is possible to further improve the stabilityof viscosity with time.

The alcohol used in the present invention is mainly ethanol. The amountof alcohol added is 5 to 40 wt %, preferably 10 to 30 wt %, morepreferably 20 to 30 wt % of the total amount of cosmetic composition. Ifthe alcohol is less than 5 wt %, it is difficult to stabilize theviscosity by the cellulose type thickening agent used in the presentinvention.

On the other hand, addition of more than 40% of alcohol has apossibility of coagulating the thickening agent.

Examples of the chelating agent used in the present invention areedetates (ethylenediaminetetraacetates) and sodium hexametaphosphate.The amount of chelating agent added is preferably 0.01 to 0.3 wt % ofthe total amount of self-tanning cosmetic gel. If it is less than 0.01wt %, it is insufficient that the suppression of the lowering of theviscosity of the cosmetic composition with time. On the other hand, notonly that the addition of more than 0.3 wt % of chelating agent isunnecessary from the point of view of the suppression of the lowering ofthe viscosity, but also the increase in the salt content produces a fearof lowering the stability of the cosmetic composition with time.

It is possible to add humectant, surfactant, ultraviolet absorber,drugs, coloring agent, powder, perfume, etc. to a self-tanning cosmeticcomposition of the present invention in the range which does not damagethe effects and the quality of the present invention.

The present invention will be explained in more detail with reference tothe following examples. However, the present invention is not restrictedto the following examples. The amount of each ingredient represents wt %so long as not specified otherwise.

EXAMPLE 1 Self-Tanning Lotion

Prescription

    ______________________________________                                        Part A                                                                        Ethyl alcohol           5.0       %                                           Vitamin E acetate       0.05                                                  POE (60) hardened castor oil                                                                          1.0                                                   2-hydroxy-4-methoxybenzophenone                                                                       0.2                                                   Paraben                 0.2                                                   Perfume                 0.02                                                  Part B                                                                        Dihydroxy acetone       5.0                                                   dl-α-tocopherol 2-L-diester potassium                                   Ascorbic phosphate      0.1                                                   Glycerin                2.0                                                   1,3-butylene glycol     2.0                                                   Pullonic L-62 (produced by Asahi Denka                                                                1.0                                                   Kogyo K.K.)                                                                   Xanthane gum            0.2                                                   Disodium edetate        0.1                                                   Ion-exchanged water     balance                                               ______________________________________                                    

Preparation Process

In the part B, disodium edetate and DHA were dissolved in theIon-exchanged water, and xanthane gum which moistened with glycerin and1,3-butylene glycol were added. Each ingredient of the part A wassufficiently dissolved and added to the part B, thereby obtaining aself-tanning lotion.

Effect test

The self-tanning lotion obtained in Example 1 was applied to the rightarm of an examinee and the self-tanning lotion produced in the same wayas in Example 1 except for not using Pullonic L-62 (ComparativeExample 1) was applied to the left arm of the examinee. Thespreadability of each self-tanning lotion to the skin and the coloredstate were evaluated by 20 examinees in accordance with the followingcriteria. The results are shown in Table 1.

Spreadability

◯: Very good

Δ: Good

×: Bad

Colored state

◯: Evenly colored

Δ: Slightly uneven

×: Uneven

                  TABLE 1                                                         ______________________________________                                                          Ex. 1                                                                         (Number of examinees)                                                                          Comp..1                                    ______________________________________                                        Spreadability                                                                            ◯                                                                        15               5                                                     Δ                                                                              4                11                                                    X      1                4                                          Colored state                                                                            ◯                                                                        17               3                                                     Δ                                                                              3                12                                                    X      0                5                                          ______________________________________                                    

As is clear from Table 1, the self-tanning lotion in Example 1 showsexcellent spreadability and colored state in spite of the small oilcontent.

EXAMPLE 2 Self-Tanning Emulsion

Prescription

    ______________________________________                                        Part A                                                                        Squalane                2.0                                                   POE (60) glycerylmonoisostearate                                                                      1.0                                                   Glycerylmonostearate    1.0                                                   Butyl paraben           0.2                                                   Perfume                 0.1                                                   Part B                                                                        1,3-butylene glycol     5.0                                                   Dehydroxy acetone (DHA) 3.0                                                   Pullonic L-64 (produced by Asahi Denka                                                                2.0                                                   Kogyo K.K.)                                                                   Hydroxyethyl cellulose  0.2                                                   Sodium citrate          0.1                                                   Sodium hexametaphosphate                                                                              0.1                                                   Ion-exchanged water     balance                                               ______________________________________                                    

Preparation Process

In the part B, sodium citrate, sodium hexametaphosphate and DHA weredissolved in the Ion-exchanged water, and Pullonic L-62 was addedthereto and the mixture was completely dissolved. Hydroxyethyl cellulosemoistened with 1,3-butylene glycol was added and the mixture was heated.Each ingredient of the part A was sufficiently dissolved, heated andadded to the part B for the purpose of emulsification.

The self-tanning cosmetic in each of Examples 1 and 2 colors the skin ina short time, easily spreads to the skin and is unlikely to cause unevencoloring.

EXAMPLE 3 Self-Tanning Gel

Prescription

    ______________________________________                                        Part A                                                                        Ethanol               30.0       %                                            Pullonic L-64         1.0                                                     Perfume               0.1                                                     Paraben               0.1                                                     Vitamin E acetate     0.01                                                    Part B                                                                        1,3-butylene glycol   5.0                                                     DHA                   3.0                                                     Hydroxypropyl cellulose                                                                             0.4                                                     Xanthane gum          0.2                                                     Chelating agent(Disodium edetate)                                                                   0.05                                                    Ion-exchanged water   balance                                                 ______________________________________                                    

Preparation Process

Dissolved part A was added to the dissolved part B, and the mixture wasadequately stirred so as to obtain a self-tanning gel.

Effect test

The type and the amount of chelate and the amount of alcohol were variedin the prescription in Example 3 (the change in the amount was adjustedby the amount of Ion-exchanged water), and the viscosity and thestability of color tone of the product with time were examined.

A sample was filled in a bottle and allowed to stand at 50° C. for 1month. The viscosity reduction ratio was measured by a B-type viscometerand a change in the color tone was visually estimated.

Criteria for estimation of a change in the color tone

◯: No change was observed.

Δ: A slight change was observed.

×: Browning was observed (colored).

The results are shown in Table

                  TABLE 2                                                         ______________________________________                                                                  Viscosity                                                                     reduction                                                   Chelating agent   ratio (%)                                                                              Browning                                   ______________________________________                                        Comp. 2 None              95       ◯                              Ex. 3   Disodium Edetate  10       ◯                              Ex. 4   Edetic Acid (EDTA)                                                                              40       ◯                              Ex. 5   Trisodium Edetate 10       ◯ to Δ                   Ex. 6   Tetrasodium Edetate                                                                             11       Δ                                    Ex. 7   Triethanolamine Edetate                                                                         15       ◯                              Ex. 8   Sodium hexametaphosphate                                                                        11       ◯                              ______________________________________                                    

It is understood from Table 2 that although a self-tanning gel composedof DHA, alcohol, water-soluble cellulose thickening agent and xanthanegum can suppress a color change, the reduction in the viscosity withtime is very large if no chelating agent is added. In other words, thereduction in the viscosity is not suppressed until addition of achelate.

Table 3, shows the relationship between the amount of chelate added andthe viscosity reduction ratio.

                  TABLE 3                                                         ______________________________________                                                   Chelate  Viscosity reduction ratio (%)                             ______________________________________                                        Comp. 2    0        95                                                        Ex.  9     0.005    60                                                        Ex. 10     0.01     20                                                        Ex. 11     0.05     15                                                        Ex. 12     0.1      12                                                        Ex. 13     0.3      8                                                         Ex. 14     0.5      8                                                         ______________________________________                                    

In Table 3, Disodium edetate was used as a chelating agent.

As is clear from Table 3, when no chelate is added, the viscosityreduction ratio is very large. It is greatly suppressed by the additionof a chelate, and the stability is increased in proportion to the amountof chelate added so long as the amount is not more than 0.3%.

In the prescription containing 0.008% of disodium edetate as a chelatingagent, the relationship between the amount of ethanol added and theviscosity reduction ratio was examined. The results are shown in Table4.

                  TABLE 4                                                         ______________________________________                                        Effect of ethanol contents                                                                          Initial                                                                       viscosity Viscosity                                              Ethanol      ratio (cps)                                                                             reduction                                     ______________________________________                                        Comp. 3   0            818      62                                            Ex. 15   10           1414      60                                            Ex. 16   20           1550      49                                            Ex. 17   30           1837      45                                            Ex. 18   50           2245      66                                            ______________________________________                                    

As is clear from Table 4, the addition of ethanol increases the initialviscosity, and when the amount of ethanol added is in the range of 20 to30%, the viscosity reduction with time is greatly suppressed.

As explained above, since the self-tanning cosmetic gel according to thepresent invention contains substantially no oil, the skin coloring speedis very fast. Furthermore, since the base has an appropriate viscosity,it is possible to spread uniformly to the skin unlike to the liquidlotion, so that uneven coloring is prevented and it produces a pleasantfeeling when it is applied to the skin.

We claim:
 1. A self-tanning cosmetic composition comprising: dihydroxyacetone, a polyoxyethylene-polyoxypropylene block copolymer surfactant,and less than 10% by weight of oil.
 2. A self-tanning cosmeticcomposition according to claim 1, wherein the content of saidpolyoxyethylene-polyoxypropylene block copolymer type surfactant is 0.1to 3 wt %.
 3. A self-tanning cosmetic gel comprising: dihydroxy acetone;water; alcohol; a water-soluble non ionic cellulose thickening agent;and a chelating agent.
 4. A self-tanning cosmetic gel according to claim3, wherein said alcohol is ethanol.
 5. A self-tanning cosmetic gelaccording to claim 3, wherein the content of said alcohol is 5 to 40 wt%.
 6. A self-tanning cosmetic gel according to claim 3, wherein thecontent of said alcohol is 10 to 30 wt %.
 7. A self-tanning cosmetic gelaccording to claim 3, wherein the content of said alcohol is 20 to 30 wt%.
 8. A self-tanning cosmetic gel according to claim 3, wherein saidchelating agent is an edetate.
 9. A self-tanning cosmetic gel accordingto claim 3, wherein the content of said chelating agent is 0.01 to 0.3wt %.
 10. A self-tanning cosmetic gel according to claim 3, wherein thecontent of said water-soluble cellulose thickening agent is 0.1 to 2 wt%.
 11. A self-tanning cosmetic gel according to claim 3, furthercomprising xanthane gum.
 12. A self-tanning cosmetic gel according toclaim 3, wherein said cosmetic gel is a transparent self-tanningcosmetic gel which contains substantially no oil.
 13. A self-tanningcosmetic composition comprising: from 1-10 wt % of dihydroxy acetone,from 0.1-3 wt % of a polyoxyethylene-polyoxypropylene block polymersurfactant, and wherein the composition contains from substantially nooil to less than 10% of oil.
 14. A self-tanning cosmetic compositioncomprising: dihydroxy acetone, from about 5-40 wt % of alcohol, from0.1-2 wt % of a non-ionic cellulose thickening agent, water, and fromabout 0.01-0.3 wt % of a chelating agent selected from the groupconsisting of edetates and sodium hexametaphosphate.
 15. Theself-tanning cosmetic composition of claim 14, further comprising from1-3 wt % of a polyoxyethylene-polyoxypropylene block copolymersurfactant.